THIS IS A REMOTE CACHE, WHICH TAKES EFFORT TO GET TO.
IT IS ROUGH UNDERFOOT.
Easegill, and the area of Leck Fell is known for its caves, and limestone features such as Easegill Kirk and Cow Dub, but there is much more to see, and learn about. This EarthCache takes you to a boulder at the side of the stream. The boulder is limestone, we are here to look for and at a specific fossil....a Horn Coral, or to be more scientific, a Rugosa coral.
Limestone is a sedimentary rock.
Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle in place. The particles that form a sedimentary rock by accumulating are called sediment. Before being deposited, the sediment was formed by weathering and erosion from the source area, and then transported to the place of deposition by water, or wind. Sedimentation may also occur as minerals precipitate from water solution or shells of aquatic creatures settle out of suspension.
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate. Many, but not all limestones are composed of skeletal fragments of marine organisms such as coral, crinoids and molluscs. Some limestone can also be formed from lime mud.
The name, Horn Coral, comes from the fact that solitary rugosa corals have the shape of a horn. A solitary rugosa coral is called a Corralum, whilst those in a colony are known as Coralites. The skeleton is the coral is made from Calcite, and the outer skeleton is known as the epithica. The top of the rugosa coral is known as the calice. The coral animal lived in this portion.
The surface of the calice is like a bike wheel, it has lines which radiate out from the centre, these are called Septa. The centre is called the Columella.
This being an earthcache, in order to log it, I ask that you answer some questions. Please send them to me, and do not include them in your log. You can send them to me by using the message facility or email, both of which can be found by looking at my profile. Alternatively, if you see me at an event, you are welcome to discuss your answers over a drink.
1. Please describe this Corralum.
2. Please describe the composition of the limestone that this fossil forms part of, in terms of grain size, other fossils, specific features.
3. Please count the septa that you can see, how many are there?